Abstract 3465: Fkbp12.6 Overexpression in Mouse Cardiac Myocytes Offers Minor Protection Against Pressure Overload-Induced Cardiac Remodeling and Failure

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Laurent Vinet ◽  
Mylène Pezet ◽  
Miresta Prévilon ◽  
Barnabas Gellen ◽  
Celine Dachez ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiac Remodeling ◽  
Protein Level ◽  
Mrna Level ◽  
Pressure Overload ◽  
Calcium Handling ◽  
Heart Catheterization ◽  
Mrna Ratio ◽  
Gravimetric Data ◽  
Actin Mrna

Alterations in RyR2 function is a hallmark of heart failure (HF). Decreased FKBP12.6 binding to RyR2 has been put forward to explain the diastolic SR Ca 2+ leakage observed in this condition. Previous work in the mouse has shown that cardiac FKBP12.6 overexpression protects against the development of myocardial infarction-induced heart failure. We tested the hypothesis that cardiac FKBP12.6 overexpression protects against transverse aortic constriction (TAC)-induced cardiac remodeling and failure. We used a mouse model of conditional cardiac-specific FKBP12.6 overexpression. Ten weeks after TAC, male transgenic mice (TG) and their wild-type controls (WT) underwent heart catheterization. Hemodynamic and gravimetric data are shown in the table . Ventricular expression of the hypertrophic gene program and calcium handling proteins were assessed by real-time PCR and Western blot, respectively. Ten weeks after TAC, the mortality rate was 23% in WT and 13% in TG (14/60 vs 5/39, ns). The percentage of mice with HF, estimated on the presence of pulmonary oedema, was 42% in WT-TAC and 32% in TG-TAC (15/36 vs 7/22, ns). BNP mRNA level increased 2.8 fold in WT-TAC (p<0.01 vs WT-Shams) and 2.4 fold in TG-TAC (p<0.01 vs TG-Shams). α-skeletal actin mRNA level increased 4.3 fold in WT-TAC (p<0.001 vs WT-Shams) and 3.8 fold in TG-TAC (p<0.001 vs TG-Shams). β-MHC/α-MHC mRNA ratio increased 2.8 fold in WT-TAC (p<0.01 vs WT-Shams) and 4.3 fold in TG-TAC (p<0.05 vs TG-Shams). RyR2 protein level decreased by 58% in WT-TAC and 41% in TG-TAC (p<0.01 and p<0.05 vs sham-operated mice, respectively). SERCA2a protein level decreased by 29% in WT-TAC and 16% in TG-TAC (p<0.01 and p<0.05 vs sham-operated mice, respectively). No statistical difference was found between TG-TAC and WT-TAC for any of these parameters. Conclusion: Cardiac FKBP 12.6 overexpression offers weak protection if any against TAC-induced cardiac remodeling and failure in the mouse.

scholarly journals Oxidative Stress as A Mechanism for Functional Alterations in Cardiac Hypertrophy and Heart Failure

Antioxidants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 931
Author(s):  
Anureet K. Shah ◽  
Sukhwinder K. Bhullar ◽  
Vijayan Elimban ◽  
Naranjan S. Dhalla
Keyword(s):  
Oxidative Stress ◽  
Heart Failure ◽  
Angiotensin Ii ◽  
Cardiac Hypertrophy ◽  
Cardiac Remodeling ◽  
Cardiac Dysfunction ◽  
Critical Role ◽  
Pressure Overload ◽  
Hypertrophied Heart ◽  
Vasoactive Hormones

Although heart failure due to a wide variety of pathological stimuli including myocardial infarction, pressure overload and volume overload is associated with cardiac hypertrophy, the exact reasons for the transition of cardiac hypertrophy to heart failure are not well defined. Since circulating levels of several vasoactive hormones including catecholamines, angiotensin II, and endothelins are elevated under pathological conditions, it has been suggested that these vasoactive hormones may be involved in the development of both cardiac hypertrophy and heart failure. At initial stages of pathological stimuli, these hormones induce an increase in ventricular wall tension by acting through their respective receptor-mediated signal transduction systems and result in the development of cardiac hypertrophy. Some oxyradicals formed at initial stages are also involved in the redox-dependent activation of the hypertrophic process but these are rapidly removed by increased content of antioxidants in hypertrophied heart. In fact, cardiac hypertrophy is considered to be an adaptive process as it exhibits either normal or augmented cardiac function for maintaining cardiovascular homeostasis. However, exposure of a hypertrophied heart to elevated levels of circulating hormones due to pathological stimuli over a prolonged period results in cardiac dysfunction and development of heart failure involving a complex set of mechanisms. It has been demonstrated that different cardiovascular abnormalities such as functional hypoxia, metabolic derangements, uncoupling of mitochondrial electron transport, and inflammation produce oxidative stress in the hypertrophied failing hearts. In addition, oxidation of catecholamines by monoamine oxidase as well as NADPH oxidase activation by angiotensin II and endothelin promote the generation of oxidative stress during the prolonged period by these pathological stimuli. It is noteworthy that oxidative stress is known to activate metallomatrix proteases and degrade the extracellular matrix proteins for the induction of cardiac remodeling and heart dysfunction. Furthermore, oxidative stress has been shown to induce subcellular remodeling and Ca2+-handling abnormalities as well as loss of cardiomyocytes due to the development of apoptosis, necrosis, and fibrosis. These observations support the view that a low amount of oxyradical formation for a brief period may activate redox-sensitive mechanisms, which are associated with the development of cardiac hypertrophy. On the other hand, high levels of oxyradicals over a prolonged period may induce oxidative stress and cause Ca2+-handling defects as well as protease activation and thus play a critical role in the development of adverse cardiac remodeling and cardiac dysfunction as well as progression of heart failure.

Abstract 375: Mechanotransduction via Titin’s N2B Element Contributes to Cardiac Remodeling

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Mathew Bull ◽  
Pooja Nair ◽  
Joshua Strom ◽  
Michael Gotthardt ◽  
Henk Granzier
Keyword(s):  
Heart Failure ◽  
Cardiac Remodeling ◽  
Mapk Pathway ◽  
Hot Spot ◽  
Pressure Overload ◽  
Volume Overload ◽  
Mitogen Activated Protein Kinase ◽  
Stress And Strain ◽  
Knock Out ◽  
Voluntary Running

Pathological remodeling is responsible for the functional deficits characteristic of heart failure patients. Understanding mechanotransduction is limited, but holds potential to provide novel therapeutic targets to treat patients with heart failure, especially those with diastolic dysfunction and preserved ejection fraction (HFpEF). Titin is the largest known protein and is abundant in muscle. It is the main contributor of passive stiffness in the heart and functions as a molecular mechano-sensor for stress and strain in the myocyte. Titin is composed of four distinct regions, (N-terminal Z-line, I-band, A-band, and C-terminal M-line), and acts as a molecular spring that is responsible for the assembly and maintenance of ultrastructure in the sarcomere. The elastic N2B element found in titin’s I-band region has been proposed as a mechano-sensor and signaling “hot spot” in the sarcomere. This study investigates the role of titin’s cardiac specific N2B element as sensor for stress and strain induced remodeling in the heart. The previously published N2B knock out (KO) mouse was subjected to a variety of stressors including transverse aortic constriction (TAC), aorto-caval fistula (ACF), chronic swimming, voluntary running and isoproterenol injections. Through chronic pathologic stress, pressure overload (TAC) and chronic volume overload (ACF), we found that the N2B element is necessary for the response to volume overload but not pressure overload as determined by changes in cardiac remodeling. Furthermore, the response to exercise either by chronic swimming or voluntary running was reduced in the N2B KO mouse. Finally, unlike the wild-type (WT) mouse, the N2B KO mouse did not respond to isoproterenol injections with hypertrophic remodeling. Ongoing work to elucidate the molecular pathways involving the N2B element and response to stress, is focused on its binding protein Four-and-a-half-LIM domains 2 (FHL2) and the mitogen activated protein kinase (MAPK) pathway. Taken together our data suggest that the N2B element contributes significantly to mechanotransduction in the heart.

Abstract 350: Atorvastatin Attenuates Pressure Overload-induced Cardiac Hypertrophy and Dysfunction Through Enhanced Autophagy

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Zhuo Zhao ◽  
Wei Wang ◽  
Hua-Ting Wang ◽  
Qing-Xin Geng ◽  
Di Zhao ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiac Hypertrophy ◽  
Western Blot ◽  
Mrna Level ◽  
Mammalian Target Of Rapamycin ◽  
Pressure Overload ◽  
Oral Gavage ◽  
Atorvastatin Treatment ◽  
Developing Heart ◽  
Phosphorylated Akt

Aims: Cardiac hypertrophy is a maladaptive change in response to pressure overload and is also an important risk for developing heart failure. We previously demonstrated that atorvastatin inhibits cardiac hypertrophy and remodeling in a mouse model of transverse aorta constriction (TAC). This study was designed to determine the regulation of atorvastatin on cardiac autophagy and its association with the development of cardiac hypertrophy and dysfunction in the mice TAC model. Methods and results: TAC or sham operations were performed in male C57/L6 mice at 8 weeks of age. Atorvastatin (50 mg/kg/day) or vehicle (normal saline) were administered daily by oral gavage to TAC mice (n=10 per group). Echocardiography and real-time PCR data showed that chronic atorvastatin treatment for four weeks significantly attenuated pressure overload-induced cardiac hypertrophy and dysfunction, as well as cardiac mRNA level of atrial natriuretic factor (ANF), a biomarker of cardiac hypertrophy and heart failure. After 4 weeks of TAC, results from electron microscopy and Western blot showed that cardiac autophagy was activated, evidenced by the increased expression of microtubule-associated protein-1 light chain 3-II (LC3-II), Beclin-1, caspase-3, and the formation of autophagosomes. Interestingly, cardiac autophagy was further increased by the treatment of atorvastatin for 4 weeks. Western blot analysis showed phosphorylated Akt and mammalian target of rapamycin (p-mTor) decreased in the heart of TAC versus sham mice, which were further decreased by atorvastatin treatment. Conclusions: These findings suggest that atorvastatin attenuates cardiac hypertrophy and dysfunction in TAC mice probably through its regulation on cardiac autophagy via Akt/mTor pathways.

scholarly journals Cardiac Protection of Valsartan on Juvenile Rats with Heart Failure by Inhibiting Activity of CaMKII via Attenuating Phosphorylation

2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Yao Wu ◽  
Feifei Si ◽  
Xiaojuan Ji ◽  
Kunfeng Jiang ◽  
Sijie Song ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiac Myocyte ◽  
Pressure Overload ◽  
The Other ◽  
Calcium Handling ◽  
Juvenile Rats ◽  
Abdominal Aortic ◽  
Calcium Handling Proteins ◽  
Increased Activity ◽  
Induce Heart Failure

Background. This study was undertaken to determine relative contributions of phosphorylation and oxidation to the increased activity of calcium/calmodulin-stimulated protein kinase II (CaMKII) in juveniles with cardiac myocyte dysfunction due to increased pressure overload. Methods. Juvenile rats underwent abdominal aortic constriction to induce heart failure. Four weeks after surgery, rats were then randomly divided into two groups: one group given valsartan (HF + Val) and the other group given placebo (HF + PBO). Simultaneously, the sham-operated rats were randomly given valsartan (Sham + Val) or placebo (Sham + PBO). After 4 weeks of treatment, Western blot analysis was employed to quantify CaMKII and relative calcium handling proteins (RyR2 and PLN) in all groups. Results. The deteriorated cardiac function was reversed by valsartan treatment. In ventricular muscle cells of group HF + PBO, Thr287 phosphorylation of CaMKII and S2808 phosphorylation of RyR2 and PLN were increased and S16 phosphorylation of PLN was decreased compared to the other groups, while Met281 oxidation was not significantly elevated. In addition, these changes in the expression of calcium handling proteins were ameliorated by valsartan administration. Conclusions. The phosphorylation of Thr286 is associated with the early activation of CaMKII rather than the oxidation of Met281.

Abstract 186: Increased STIM1 Expression Results in Altered Calcium Handling and Heart Failure

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Robert N Correll ◽  
Sanjeewa A Goonasekera ◽  
Jop H van Berlo ◽  
Adam R Burr ◽  
Federica Accornero ◽  
...  
Keyword(s):  
Heart Failure ◽  
Transgenic Mice ◽  
Cardiac Disease ◽  
Functional Performance ◽  
Pressure Overload ◽  
Calcium Handling ◽  
Activated T Cells ◽  
Baseline Activity ◽  
Mitochondrial Pathology ◽  
Dependent Protein

Stromal interaction molecule 1 (STIM1) is a Ca2+ sensor that partners with Orai1, resulting in store-operated Ca2+ entry (SOCE) that is important for maintaining endoplasmic reticulum (ER) Ca2+ homeostasis. STIM1 is expressed in the heart and upregulated during disease, but its role in disease progression is unclear. In this study we used transgenic mice with STIM1 overexpression in the heart to model the known increase of this protein in response to cardiac disease. We found that STIM1 transgenic myocytes showed elevated Ca2+ entry following store depletion and STIM1 co-localized with the type 2 ryanodine receptor (RyR2) in the sarcoplasmic reticulum (SR). In addition, STIM1 transgenic mice exhibited sudden cardiac death as early as 6 weeks of age, while mice that survived past 12 weeks developed cardiac hypertrophy that progressed to heart failure, pulmonary edema, activation of the fetal gene program, alterations in mitochondrial structure, and reduced ventricular functional performance. When pre-symptomatic STIM1 transgenic mice were subjected to disease stimuli including pressure overload stimulation or neurohumoral agonist infusion, they showed greater pathology compared to control mice. STIM1 elevation also disrupted normal Ca2+ handling in cardiac myocytes, which showed spontaneous Ca2+ transients that could be inhibited by the SOCE blocker SKF-96265, as well as increased diastolic Ca2+ levels and elevated Ca2+ spark frequency. In keeping with this increase in Ca2+ cycling we also found that STIM1 elevation resulted in an increased baseline activity of cardiac nuclear factor of activated T-cells (NFAT) and Ca2+/calmodulin-dependent protein kinase II (CaMKII). This increased CaMKII activity did not, however, translate into additional RyR2 phosphorylation, suggesting that the augmented Ca2+ spark frequency observed was likely due to an elevation in SR Ca2+ load. Our results suggest that increased STIM1 expression elicits augmented Ca2+ entry, SR Ca2+ load and Ca2+ spark frequency, that leads to mitochondrial pathology and the induction of Ca2+ sensitive hypertrophic signaling pathways that contribute to cardiac disease.

Abstract 354: The Role of the Liver Heart Axis During Cardiac Remodeling

2020 ◽  
Vol 127 (Suppl_1) ◽  
Author(s):  
Soichiro Usui ◽  
Shin-ichiro Takashima ◽  
Kenji Sakata ◽  
Masa-aki Kawashiri ◽  
Masayuki Takamura
Keyword(s):  
Heart Failure ◽  
Insulin Resistance ◽  
Cardiac Remodeling ◽  
Pressure Overload ◽  
Normal Subjects ◽  
Serum Levels ◽  
Lung Weight ◽  
Reduced Ejection Fraction ◽  
Hepatic Expression

Background: Hepatokine selenoprotein P (SeP) contributes to insulin resistance and hyperglycemia in patients with type 2 diabetes. Although clinical studies suggest the insulin resistance is an independent risk factor of heart failure and inhibition of SeP protects the heart from ischemia reperfusion injury, the role of SeP in pathogenesis of chronic heart failure is not well understood. Objective: We examined the role of SeP in the regulation of cardiac remodeling in response to pressure overload. Methods and Results: We measured serum SeP levels in 22 patients for heart failure with reduced ejection fraction (HFrEF; LVEF<50%) and 22 normal subjects. Serum levels of SeP were significantly elevated in patients with HFrEF compared to in normal subjects (3.55 ± 0.43 vs 2.98 ± 0.43, p<0.01). To examine the role of SeP in cardiac remodeling, SeP knockout (KO) and wild-type (WT) mice were subjected to pressure overload (transverse aortic constriction (TAC)) for 2 weeks. The mortality rate following TAC was significantly decreased in SeP KO mice compared to WT mice (22.5 % in KO mice (n=40) vs 52.3 % in WT mice (n=39) p<0.01). LV weight/tibial length (TL) was significantly smaller in SeP KO mice than in WT mice (6.75 ± 0.24 vs 8.33 ± 0.32, p<0.01). Lung weight/TL was significantly smaller in SeP KO than in WT mice (10.46 ± 0.44 vs 16.38 ± 1.12, p<0.05). Interestingly, hepatic expression of SeP in WT was significantly increased by TAC. To determine whether hepatic overexpression of SeP affects TAC-induced cardiac hypertrophy, a hydrodynamic injection method was used to generate mice that overexpress SeP mRNA in the liver. Hepatic overexpression of SeP in SeP KO mice lead to a significant increase in LV weight/TL and Lung weight/TL after TAC compared to that in other SeP KO mice. Conclusions: These results suggest that serum levels of SeP were elevated in patients with heart failure with reduced ejection fraction and cardiac pressure overload induced hepatic expression of SeP in mice model. Gene deletion of SeP attenuated cardiac hypertrophy and dysfunction in response to pressure overload in mice. SeP possibly plays a pivotal role in promoting cardiac remodeling through the liver-heart axis.

3,3-Dimethyl-1-butanol attenuates cardiac remodeling in pressure-overload-induced heart failure mice

2020 ◽  
Vol 78 ◽  
pp. 108341 ◽  
Author(s):  
Guangji Wang ◽  
Bin Kong ◽  
Wei Shuai ◽  
Hui Fu ◽  
Xiaobo Jiang ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiac Remodeling ◽  
Pressure Overload

scholarly journals Proteasome inhibition decreases cardiac remodeling after initiation of pressure overload

2008 ◽  
Vol 295 (4) ◽  
pp. H1385-H1393 ◽  
Author(s):  
Nadia Hedhli ◽  
Paulo Lizano ◽  
Chull Hong ◽  
Luke F. Fritzky ◽  
Sunil K. Dhar ◽  
...  
Keyword(s):  
Heart Failure ◽  
Ejection Fraction ◽  
Cardiac Remodeling ◽  
Ventricular Remodeling ◽  
Pressure Overload ◽  
Proteasome Inhibition ◽  
Aortic Banding ◽  
Lung Weight ◽  
Cross Sectional ◽  
Myocyte Apoptosis

We tested the possibility that proteasome inhibition may reverse preexisting cardiac hypertrophy and improve remodeling upon pressure overload. Mice were submitted to aortic banding and followed up for 3 wk. The proteasome inhibitor epoxomicin (0.5 mg/kg) or the vehicle was injected daily, starting 2 wk after banding. At the end of the third week, vehicle-treated banded animals showed significant ( P < 0.05) increase in proteasome activity (PA), left ventricle-to-tibial length ratio (LV/TL), myocyte cross-sectional area (MCA), and myocyte apoptosis compared with sham-operated animals and developed signs of heart failure, including increased lung weight-to-TL ratio and decreased ejection fraction. When compared with that group, banded mice treated with epoxomicin showed no increase in PA, a lower LV/TL and MCA, reduced apoptosis, stabilized ejection fraction, and no signs of heart failure. Because overload-mediated cardiac remodeling largely depends on the activation of the proteasome-regulated transcription factor NF-κB, we tested whether epoxomicin would prevent this activation. NF-κB activity increased significantly upon overload, which was suppressed by epoxomicin. The expression of NF-κB-dependent transcripts, encoding collagen types I and III and the matrix metalloprotease-2, increased ( P < 0.05) after banding, which was abolished by epoxomicin. The accumulation of collagen after overload, as measured by histology, was 75% lower ( P < 0.05) with epoxomicin compared with vehicle. Myocyte apoptosis increased by fourfold in hearts submitted to aortic banding compared with sham-operated hearts, which was reduced by half upon epoxomicin treatment. Therefore, we propose that proteasome inhibition after the onset of pressure overload rescues ventricular remodeling by stabilizing cardiac function, suppressing further progression of hypertrophy, repressing collagen accumulation, and reducing myocyte apoptosis.

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